Battery cell, method for manufacturing the same, battery device, energy storage device, power consumption device

Abstract

The application relates to the technical field of energy storage, and discloses a battery monomer, a preparation method of the battery monomer, a battery device, an energy storage device and a power utilization device, which can be used for improving the working performance of the battery monomer. The battery monomer comprises a shell, a top cover assembly and an electrode assembly. The shell is provided with an opening. The top cover assembly comprises a cover body arranged at the opening, and a positive electrode post and a negative electrode post connected with the cover body. The electrode assembly is arranged in the shell, and comprises a pole piece arranged in a winding mode from inside to outside. The pole piece is provided with a tab, and the tab is connected with the electrode post. In a first direction, the pole piece comprises a first part and a second part located at two ends of the first part. The electrode assembly has a corrugated structure between at least two adjacent layers of pole pieces within a preset number of turns from inside to outside. The amplitude of the corrugated structure in the first part is smaller than the amplitude of the corrugated structure in the second part.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a battery cell and its preparation method, a battery device, an energy storage device, and an electrical device. Background Technology

[0002] With the continuous development of new energy technologies, the demand for energy storage systems is also increasing. Energy storage systems can effectively store electrical energy and output it when needed. Energy storage systems use individual battery cells as energy storage units. These battery cells have good charge-discharge cycle characteristics, enabling the formation of electrochemical energy storage systems with a wide range of applications.

[0003] As a crucial component of energy storage systems, individual battery cells significantly impact the overall performance of the system. In particular, as the energy storage units, the performance of individual battery cells determines the amount of electrical energy the system can store and its charge / discharge efficiency. Therefore, designing the structure of individual battery cells to improve their performance is a critical issue. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell and its preparation method, battery device, energy storage device, and power consumption device, which can help improve the working performance of the battery cell.

[0005] To address the aforementioned technical problems, embodiments of this application provide a battery cell. The battery cell includes a housing, a top cover assembly, and an electrode assembly. The housing has an opening. The top cover assembly includes a cover disposed at the opening, and a positive electrode post and a negative electrode post connected to the cover. The electrode assembly is disposed within the housing and includes electrode sheets wound from the inside out. Each electrode sheet has tabs connected to electrode posts. Along a first direction, the electrode sheet includes a first portion and second portions located at both ends of the first portion. The electrode assembly has a corrugated structure between at least two adjacent layers of electrode sheets within a predetermined number of turns from the inside out. The amplitude of the corrugated structure in the first portion is smaller than the amplitude of the corrugated structure in the second portion.

[0006] The embodiments of this application also provide a method for preparing a battery cell, the method comprising: The electrode is wound, and different magnitudes of force are applied to the first and second regions of the electrode distributed along the first direction before the electrode is wound. After the electrode sheet is wound a predetermined number of turns, the application of different magnitudes of force to the first and second regions of the electrode sheet distributed along the first direction is stopped before the electrode sheet is wound, and the electrode sheet is wound again to obtain an electrode assembly. Place the electrode assembly into the housing; The top cover assembly is connected to the opening of the housing, and the terminal of the top cover assembly is connected to the tab of the electrode plate to form a battery cell.

[0007] The embodiments of this application also provide a battery device, which includes the battery cell described above, or a battery cell manufactured by the method described above for preparing the battery cell.

[0008] The embodiments of this application also provide an energy storage device, which includes the battery device described above, and the battery device is used to store electrical energy.

[0009] The embodiments of this application also provide an electrical device, which includes the battery device described above, and the battery device is used to provide electrical energy.

[0010] The battery cell, its preparation method, battery device, energy storage device, and power consumption device provided by the embodiments of this application form a corrugated structure in the inner ring electrode sheet of the core. The corrugated structure can better release the stress of the inner ring electrode sheet. The amplitude of the corrugated structure in the first part of the inner ring electrode sheet is smaller than that in the second part, which can ensure that the inner ring electrode sheet forms a more obvious undulation at the edge. That is, the inner ring electrode sheet forms a corrugated structure with partitioned distribution along the width direction, which can compensate for the interlayer contact pressure of the rolled inner ring electrode sheet, thereby improving the uniformity of the interlayer contact state of the inner ring of the core, and helping to mitigate the deformation accumulation effect caused by local stress concentration during cyclic expansion, thereby improving the working performance of the battery cell.

[0011] In some embodiments, the size of the electrode assembly along the first direction is 200mm to 600mm.

[0012] In some embodiments, along the first direction, the second part includes an adjacent third part and a fourth part, the third part being located between the first part and the fourth part, and the amplitude of the corrugated structure of the third part being smaller than the amplitude of the corrugated structure of the fourth part.

[0013] In some implementations, the mean difference between the amplitude of the corrugated structure in the third part and the amplitude of the corrugated structure in the fourth part is greater than or equal to 3µm.

[0014] In some embodiments, the amplitude of the corrugated structure in the first part is 5µm to 40µm, the amplitude of the corrugated structure in the third part is 10µm to 60µm, and the amplitude of the corrugated structure in the fourth part is 15µm to 80µm.

[0015] In some embodiments, the maximum depth of the corrugated structure in the first part is less than or equal to 25µm, the maximum depth of the corrugated structure in the third part is 5µm to 40µm, and the maximum depth of the corrugated structure in the fourth part is 10µm to 70µm.

[0016] In some embodiments, along the first direction, the dimensions of the first, third, and fourth portions are greater than or equal to 5% of the dimensions of the electrode assembly, or the dimensions of the first, third, and fourth portions are greater than or equal to 10 mm.

[0017] In some embodiments, the amplitude of the corrugated structure in the first part is 5µm to 60µm, and the amplitude of the corrugated structure in the second part is 10µm to 80µm.

[0018] In some embodiments, along the first direction, the size of the first part is 40% to 80% of the size of the electrode assembly, and the size of the second part is 10% to 30% of the size of the electrode assembly.

[0019] In some implementations, the preset number of turns is less than or equal to 0.3N, where N is the number of turns of the electrode.

[0020] In some implementations, the ratio between the standard deviation and the mean of the amplitude of the corrugated structure located in the first and / or second parts of different layers is less than or equal to 0.3.

[0021] In some embodiments, the gap between the first part of two adjacent electrode layers with a corrugated structure is less than or equal to 25µm, and the gap between the second part of two adjacent electrode layers with a corrugated structure is 5µm to 60µm.

[0022] In some embodiments, the electrode includes a current collector and an active material layer stacked together. Along a first direction, the electrode has adjacent coated and uncoated areas, the active material layer is located in the coated area, and a corrugated structure is formed in the coated area.

[0023] In some embodiments, along the second direction, the electrode includes a main body portion and curved portions located on both sides of the main body portion, and a corrugated structure is formed on the main body portion, wherein the second direction is a direction intersecting the first direction.

[0024] In some embodiments, the electrode assembly further includes a diaphragm disposed adjacent to the electrode sheet. Along a first direction, the diaphragm includes a middle portion and edge portions located at both ends of the middle portion. At least two adjacent layers of the diaphragm within a predetermined number of turns from the inside to the outside of the electrode assembly have a corrugated structure. The amplitude of the corrugated structure in the middle portion is smaller than the amplitude of the corrugated structure in the edge portion. Attached Figure Description

[0025] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0026] Figure 1This is a three-dimensional structural diagram of a battery cell provided in an embodiment of this application; Figure 2 This is a schematic diagram of the exploded structure of a single battery cell provided in an embodiment of this application; Figure 3 This is an exploded structural diagram of the top cover assembly in a battery cell provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the electrode assembly in the battery cell provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of a single electrode assembly in a battery cell provided in the embodiments of this application; Figure 6 It is along Figure 5 Schematic diagram of the cross-sectional structure along the MM direction; Figure 7 yes Figure 6 A magnified schematic diagram of the partial structure at point A in the middle; Figure 8 It is along Figure 5 A schematic diagram of the cross-sectional structure along the NN direction; Figure 9 This is a flowchart of the battery cell preparation method provided in the embodiments of this application; Figure 10 This is a schematic diagram of the structure of the partitioned pressure roller provided in the embodiment of this application; Figure 11 This is a schematic diagram of the structure of the compensation roller provided in the embodiments of this application; Figure 12 This is a schematic diagram of the battery pack structure provided in the embodiments of this application; Figure 13 This is an exploded structural diagram of the battery pack provided in an embodiment of this application; Figure 14 This is a schematic diagram of the energy storage cabinet provided in the embodiments of this application; Figure 15 This is a schematic diagram of the structure of the energy storage container provided in the embodiments of this application; Figure 16 This is a schematic diagram of the structure of a mobile phone provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this application to enable readers to better understand this application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in this application can be implemented. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0029] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0030] As energy sources become increasingly diverse, the importance of energy storage is also rising. Battery devices formed from individual battery cells are a widely used energy storage structure; for example, lithium-ion battery devices are ubiquitous in industrial production and daily life. Lithium-ion batteries are widely used due to their high energy density, long cycle life per cell, high efficiency, and clean, pollution-free operation. Prismatic lithium-ion batteries, in particular, offer both high structural strength and high energy density. Furthermore, their relatively simple structure and ease of capacity expansion make them a crucial option for increasing energy density by improving the capacity of individual battery cells.

[0031] In the manufacturing process of high-capacity prismatic batteries with wound cells, wide electrode sheets are wound along the width direction ( Figure 6Uneven force distribution (in the direction indicated by the middle arrow X) can lead to poor uniformity of the internal structure of the core. As battery cells rapidly develop towards larger capacities, high-capacity prismatic batteries such as 314Ah and 587Ah generally use wider electrodes; for example, electrodes wider than 200mm are used in the winding process. When using wider electrodes for winding, there are significant differences in local tension and contact pressure between the central region and the two edge regions. Currently, there is a lack of active control methods along the width direction during electrode winding, resulting in a disordered distribution of interlayer deformation characteristics within the core along the width direction. This difference in interlayer deformation is continuously amplified under the layer superposition effect, forming a random residual morphology that is difficult to define and quantify, thus causing problems such as differences in interlayer contact pressure, accumulation of local wrinkles in the inner ring, and local stress concentration after cycling.

[0032] In other words, one way to improve the energy density of high-capacity prismatic batteries is to increase the width of the electrode sheets, thereby achieving a higher stacking height of active materials within a limited cross-sectional size of the casing. However, the continuous increase in electrode width places stringent requirements on the interlayer deformation control of the core, and the contact effect of different regions of the electrode sheet along the width direction becomes a target that needs to be controlled in high-capacity batteries.

[0033] In existing battery cells, the electrodes are assumed to be subjected to uniform stress and have consistent contact. However, in large-capacity batteries with a larger width, boundary effects, uneven roller contact, and differences in lateral stiffness distribution lead to a significant tension gradient between the central and edge regions of the electrode, resulting in uneven interlayer residual deformation along the width direction.

[0034] The battery cells provided in some embodiments of this application compensate for the difference in tension distribution in the width direction, so that the wide electrode sheet is continuously in a state of force matching in the width direction throughout the entire winding process, ensuring that the electrode sheet can reduce the generation of local bending strain difference and contact pressure difference in the width direction in each turn.

[0035] Specifically, the battery cell provided in some embodiments of this application has a core with at least two different morphological sections along its width direction, each section having a measurable interlayer deformation characteristic. Furthermore, this interlayer deformation characteristic is actively controlled by a width-direction differentiated force application mechanism, which can compensate for the tension distribution differences in the electrode width direction, thereby ensuring that the inner ring of the electrode assembly in the battery cell has a relatively uniform contact pressure.

[0036] The following is combined Figures 1 to 8 This application describes the structure of a battery cell provided in some embodiments.

[0037] like Figure 1 and Figure 2As shown, some embodiments of this application provide a battery cell 10 including a housing 11, a top cover assembly 12, and an electrode assembly 13. The housing 11 has an opening 111. The top cover assembly 12 includes a cover 121 disposed at the opening 111 and an electrode post connected to the cover 121. The electrode assembly 13 is disposed within the housing 11, and the electrode assembly 13 includes electrode sheets 130 wound from the inside out. Figure 6 As shown), electrode 130 is provided with a tab, which is connected to the electrode post. Along the first direction ( Figure 6 (In the direction indicated by the middle arrow X), the electrode 130 includes a first part 131 and a second part 132 located at both ends of the first part 131. The electrode assembly 13 has a corrugated structure in at least two adjacent layers of electrode 130 within a preset number of turns from the inside to the outside. The amplitude of the corrugated structure of the first part 131 is smaller than the amplitude of the corrugated structure of the second part 132.

[0038] The housing 11 is the part of the battery cell 10 that houses the electrode assembly 13, and the housing 11 is hollow inside. The housing 11 and the cover 121 cooperate to form the encapsulation part of the battery cell 10. The housing 11 has high mechanical strength, providing protection for the internally installed components and preventing the electrode assembly 13 from being affected by the external environment. Figure 1 and Figure 2 The casing 11 is formed by four side walls enclosing the bottom wall to create an internal space with an opening 111 on one side. In practice, the casing 11 may have fewer than four or more side walls, forming a roughly square outer shell. The casing 11 and the cover 121 can be made of lightweight aluminum. In addition, an insulating film can be used to wrap the outside of the casing 11 of the battery cell 10 for protection; the insulating film can be a blue film.

[0039] Electrode assembly 13 is disposed within housing 11. Electrode assembly 13 includes a positive electrode 1301, a negative electrode 1302, and a separator 1303 separating the positive electrode 1301 and the negative electrode 1302. Figure 8 As shown, the positive electrode 1301 is provided with a positive electrode tab 1304, and the negative electrode 1302 is provided with a negative electrode tab 1305. The positive electrode tab 1304 is connected to the positive electrode post 122 passing through the first electrode post hole 1211 of the cover 121 in the same current path, and the negative electrode tab 1305 is connected to the negative electrode post 123 passing through the second electrode post hole 1212 of the cover 121 in the same current path. Figure 4 The structure of the electrode assembly 13 housed within the housing 11 in this embodiment is shown. Figure 5A single electrode assembly 13 is illustrated. This embodiment illustrates an example where the housing 11 contains two electrode assemblies 13. In practice, the housing 11 may contain one or more electrode assemblies 13.

[0040] Electrode assembly 13 is the part of the battery cell 10 that works with the electrolyte to achieve electrochemical energy storage. During charging and discharging, lithium ions can move between the positive electrode 1301 and the negative electrode 1302. Electrode assembly 13 is formed by winding the positive electrode 1301, the negative electrode 1302, and the separator 1303. The top surface is where the different tabs of electrode assembly 13 are led out; the positive electrode 1301 leads out the positive tab 1304, and the negative electrode 1302 leads out the negative tab 1305. For example... Figure 4 and Figure 5 As shown, the positive electrode tab 1304 and negative electrode tab 1305, extending from the top surface of the electrode assembly 13, are separately disposed in two areas. The positive electrode tab 1304 and negative electrode tab 1305 are connected to different connecting pieces, which act as transitions to connect the positive electrode tab 1304 to the positive electrode post 122 and the negative electrode tab 1305 to the negative electrode post 123. In practice, the positive electrode tab 1304 may have a gap between it and the top surface of the electrode assembly 13, or it may be attached to the top surface. Similarly, the negative electrode tab 1305 may have a gap between it and the top surface of the electrode assembly 13, or it may be attached to the top surface.

[0041] The electrode tab structure is located on the top of the housing 11. To reduce the space occupied inside the housing 11, the electrode tab is usually folded. The top of the housing 11 refers to the portion on the side where the opening 111 is located. The top of the housing 11 also has a top cover assembly 12, the structure of which is as follows: Figure 3As shown. The cover 121 in the top cover assembly 12 forms the base for connecting other components. Simultaneously, the cover 121 can be equipped with an explosion-proof valve structure 1213 and an explosion-proof valve patch 1214 for protection. One side of the bottom surface of the top cover assembly 12 is connected to the electrode assembly 13, and one side of the top surface of the top cover assembly 12 is connected to the first and second electrodes. The protruding portions of the first and second electrodes can be connected to the top cover assembly 12 of another battery cell 10. The bottom of the positive electrode post 122 is welded to the first connecting piece 124, and the bottom of the negative electrode post 123 is welded to the second connecting piece 125. The first connecting piece 124 has a first protrusion 1241 connected to the positive electrode tab 1304, and the second connecting piece 125 has a second protrusion 1251 connected to the negative electrode tab 1305. Meanwhile, the first connecting piece 124 can be provided with a first through hole 1242 to position the positive terminal 122, and the second connecting piece 125 can be provided with a second through hole 1252 to position the negative terminal 123. The positive terminal 122 can be insulated from the lower plastic 128 and the cover 121 by the first upper plastic 126, and the negative terminal 123 can be insulated from the lower plastic 128 and the cover 121 by the second upper plastic 127. The lower plastic 128 can be provided with a first through hole 1281 for the positive terminal 122 to pass through, and a second through hole 1282 for the negative terminal 123 to pass through.

[0042] The top surface of the positive electrode post 122 can be welded with the first electrode plate, and the top surface of the negative electrode post 123 can be welded with the second electrode plate, so as to form a series or parallel connection with other battery cells 10.

[0043] The first direction corresponds to the width direction of the electrode 130, that is, the first direction is parallel to the width direction of the electrode 130. The first part 131 is located in the central region of the electrode 130 along the width direction, and the second part 132 is located in the edge region of the electrode 130 along the width direction, that is, the second part 132 is farther away from the center of the electrode 130 than the first part 131. The first part 131 and the second part 132 are distributed along the width direction of the electrode 130. After the electrode 130 is wound to form a core, the first part 131 is located in the middle of the core, and the second part 132 is located at the end of the core. Figure 6 The cross-sectional structure of the core along the vertical direction is illustrated for ease of explanation. Figure 6 The diagram illustrates the portion of the winding core from the center to one side surface. The tab structure can be formed in... Figure 6 The corrugated structure is formed on one or both edges of the electrode 130 along the width direction. The first part 131 is closer to the center region of the electrode 130 along the width direction than the second part 132.

[0044] The electrode assembly 13 has a corrugated structure on the electrode sheet 130 within a preset number of turns. Specifically, the inner circle electrode sheet 130a (i.e., the portion of the electrode sheet 130 near the inner circle of the core after winding) near the winding center has a corrugated structure. The corrugated electrode sheet 130 can be either a positive electrode sheet 1301 or a negative electrode sheet 1302. The separator 1303 located between the positive electrode sheet 1301 and the negative electrode sheet 1302 can also have a corrugated structure. The corrugated structure means that the cross-section of the electrode sheet 130 has an uneven shape. That is, the electrode sheet 130 includes multiple concave and convex portions alternately distributed along a first direction or in a direction intersecting the first direction. The concave and convex portions form shapes that bulge in different directions, making the electrode sheet 130 as a whole present a corrugated structure.

[0045] The amplitude B of the corrugated structure corresponds to the distance between the concave or convex part and the ideal plane of the electrode 130 (i.e., the center plane of the electrode 130 when it is in a flat state), that is, the distance between the concave or convex part and the ideal plane of the electrode 130. Figure 6 and Figure 7 The convex dimension of the plane (shown by the dashed line). The magnitude of the amplitude is related to the degree of unevenness in different parts of the electrode 130. The larger the amplitude, the greater the degree of unevenness in the electrode 130, and the more obvious the undulation of the cross-sectional shape of the electrode 130. The smaller the amplitude, the smaller the degree of unevenness in the electrode 130, and the smoother the undulation of the cross-sectional shape of the electrode 130. By making the amplitude of the corrugated structure of the first part 131 smaller than the amplitude of the corrugated structure of the second part 132, the cross-sectional shape of the second part 132 can have a more obvious undulation, thereby making the unevenness of the edge part of the inner ring electrode 130a along the width direction greater. This ensures that the edge part of the inner ring electrode 130a releases stress better and avoids severe deformation or even breakage of the edge part of the inner ring electrode 130a due to stress. In practice, the amplitude of the corrugated structure of different parts of the electrode 130 can be obtained by sampling and calculation. For example, a section of corrugated structure containing a specific number (one, two, four or six) of concave and / or convex parts can be selected, and the protrusion size of each concave and / or convex part relative to the ideal plane of the electrode 130 can be calculated. The maximum value or average value can be used as the amplitude of the corrugated structure of the corresponding part of the electrode 130.

[0046] When two adjacent electrode layers 130 form a corrugated structure with zoned distribution, a regular zoned structure can be formed between the electrode layers, resulting in a similar corrugated structure between the electrode layers. Furthermore, the corrugated structure between the electrode layers and the corrugated structure of the electrode 130 form the same zoned distribution pattern; that is, between two adjacent electrode layers 130, the corrugated structure is distributed with different amplitudes in the end and middle regions of the core. The corrugated structure between the electrode layers is zoned along the width direction inside the core, which significantly reduces the difference in interlayer contact pressure between different regions of the inner ring of the core along the width direction, thus improving the uniformity of the interlayer contact state in the inner ring. Moreover, it helps to mitigate the deformation accumulation effect caused by local stress concentration during cyclic expansion, improving the structural stability of the battery cell 10 under long-cycle conditions.

[0047] In some embodiments of this application, the battery cell 10 has a corrugated structure formed in the inner ring electrode 130a of the core. The corrugated structure can effectively release the stress of the inner ring electrode 130a. The amplitude of the corrugated structure in the first part 131 of the inner ring electrode 130a is smaller than the amplitude of the corrugated structure in the second part 132. This ensures that the inner ring electrode 130a forms a more obvious undulation at the edge, that is, the inner ring electrode 130a forms a corrugated structure with partitioned distribution along the width direction. This can compensate for the interlayer contact pressure of the inner ring electrode 130a of the core, thereby improving the uniformity of the interlayer contact state of the inner ring of the core, and helping to mitigate the deformation accumulation effect caused by local stress concentration during cyclic expansion, thereby improving the working performance of the battery cell 10.

[0048] In some embodiments, the size W of the electrode assembly 13 along the first direction can be 200mm to 600mm.

[0049] The dimension W of the electrode assembly 13 along the first direction corresponds to the width of the electrode assembly 13, that is, the width of the electrode assembly 13 can be 200mm to 600mm. In practice, the dimension W of the electrode assembly 13 along the first direction can be 200mm to 300mm, 300mm to 400mm, 400mm to 500mm, or 500mm to 600mm. For example, the dimension W of the electrode assembly 13 along the first direction can be 200mm, 250mm, 300mm, 350mm, 400mm, 450mm, 500mm, 550mm, or 600mm.

[0050] The electrode assembly 13 has a dimension W of at least 200 mm along the first direction, which means that the electrode sheet 130 also has a relatively large dimension along the first direction. In other words, the electrode sheet 130 in the electrode assembly 13 is a wide electrode sheet 130, which can be referred to as a wide electrode sheet. Due to its large width, the wide electrode sheet is easily affected by stress during the winding process. Furthermore, the stress difference between the central and edge portions of the wide electrode sheet is significant, resulting in different degrees of stress impact on each part during winding.

[0051] Specifically, during the winding process, the closer the electrode 130 is to the inner ring, the more curved its shape becomes, and the greater the stress it experiences. Wide electrodes, in particular, tend to generate greater stress at their edges. Therefore, when the electrode 130 has a larger width, the amplitude of the corrugated structure of the first part 131 of the inner ring electrode 130a can be smaller than the amplitude of the corrugated structure of the second part 132. This ensures that the edges of the inner ring electrode 130a are not subjected to significant stress, and also ensures effective contact between the middle and edge portions of adjacent electrodes 130, as well as effective electrolyte wetting at all points on the electrode 130, thereby ensuring the performance of the battery cell 10.

[0052] In some embodiments, the amplitude of the corrugated structure of the first part 131 can be 5µm to 60µm, and the amplitude of the corrugated structure of the second part 132 can be 10µm to 80µm.

[0053] In practice, the amplitude of the corrugated structure of the first part 131 can be 5µm~10µm, 10µm~20µm, 20µm~40µm, or 40µm~60µm. For example, the amplitude of the corrugated structure of the first part 131 can be 5µm, 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 55µm, or 60µm.

[0054] The amplitude of the corrugated structure of the second part 132 can be 10µm~20µm, 20µm~40µm, 40µm~60µm, or 60µm~80µm. For example, the amplitude of the corrugated structure of the second part 132 can be 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 60µm, 70µm, or 80µm.

[0055] By controlling the amplitude of the corrugated structure in different sections of the electrode 130, the degree of unevenness in different parts of the electrode 130 can be controlled. This results in a greater degree of unevenness at the edge of the inner electrode 130a along its width, ensuring better stress release at the edge and preventing severe deformation or even breakage due to stress. Furthermore, by keeping the amplitude of the corrugated structure between the center and edge of the electrode 130 within a certain range, the tension differences between different parts of the electrode 130 can be better matched, ensuring good interlayer contact between different parts of the electrode 130.

[0056] In some embodiments, along a first direction, the second part 132 may include a third part 133 and a fourth part 134 disposed adjacent to each other. The third part 133 is located between the first part 131 and the fourth part 134, and the amplitude of the corrugated structure of the third part 133 is smaller than the amplitude of the corrugated structure of the fourth part 134.

[0057] In other words, the second part 132 includes a third part 133 and a fourth part 134 distributed along the width direction of the electrode 130, with the fourth part 134 being closer to the edge of the electrode 130 than the third part 133. Figure 6 As can be seen, the electrode 130 can be sequentially divided into a fourth part 134, a third part 133, a first part 131, a third part 133, and a fourth part 134 along its width. The first part 131 corresponds to the central portion of the electrode 130 along its width, the third part 133 corresponds to the transition portion of the electrode 130 along its width, and the fourth part 134 corresponds to the edge portion of the electrode 130 along its width. The electrode 130 forms a greater number of partitioned structures along its width, and the amplitude of the corrugated structures in different parts varies, thus causing the electrode 130 to form an uneven shape with a constantly changing degree of undulation from the edge to the center.

[0058] The fourth part 134 is located on the side of the third part 133 away from the first part 131, and the amplitude of the corrugated structure of the fourth part 134 is greater than that of the corrugated structure of the third part 133. The third part 133 can act as a transition between the first part 131 and the fourth part 134, avoiding a large difference in the degree of undulation between the center and edge parts of the electrode sheet 130 along the width direction. By setting the transition part, the control of the corrugated structure of different parts of the electrode sheet 130 can be more precise, forming a larger number of partitions to accommodate the winding of wide electrode sheets. By increasing the number of partitions in the corrugated structure of the electrode sheet 130, the shape of the inner ring of the formed core can be more stable, ensuring the interlayer contact effect of the inner ring electrode sheet 130a, thereby ensuring the working performance of the battery cell 10.

[0059] In practice, the number of partitions in the corrugated structure of electrode 130 can be greater than three. For example, the corrugated structure of electrode 130 can form four, five, or six partitions from the center to the edge of electrode 130.

[0060] In some embodiments, the mean difference between the amplitude of the corrugated structure of the third part 133 and the amplitude of the corrugated structure of the fourth part 134 can be greater than or equal to 3µm.

[0061] In other words, the difference in the mean amplitude of the corrugated structure of two adjacent parts in the second part 132 can be controlled within a range of not less than 3µm. By controlling the mean difference in the amplitude of the corrugated structure of two adjacent parts of the electrode 130, a certain difference in the amplitude of the corrugated structure of the two adjacent parts can be formed, thereby making the degree of undulation of the corrugated structure of the two adjacent parts of the electrode 130 different enough to match the tension difference.

[0062] In practice, the mean value better represents the overall structural state of the corrugated structure, eliminating interference from accidental factors such as local burrs, foreign objects, pressure marks, and measurement noise. It can also be combined with median difference and quantile difference as auxiliary judgment parameters.

[0063] The mean difference in the corrugated structure between adjacent portions of the electrode can be greater than or equal to 5µm or greater than or equal to 10µm. The mean difference in the amplitude of the corrugated structure between the center and the edge portions can be greater than or equal to 10µm or greater than or equal to 20µm.

[0064] In addition, other factors can be used as auxiliary control factors, such as the maximum depth of the corrugated structure and the interlayer gap between adjacent electrode layers. The maximum depth difference of the corrugated structure between adjacent portions of the electrode can be controlled within 5µm to 10µm, and the interlayer gap difference between adjacent electrode layers can be controlled within 3µm to 5µm.

[0065] In some embodiments, the amplitude of the corrugated structure of the first part 131 can be 5µm to 40µm, the amplitude of the corrugated structure of the third part 133 can be 10µm to 60µm, and the amplitude of the corrugated structure of the fourth part 134 can be 15µm to 80µm.

[0066] In practice, the amplitude of the corrugated structure of the first part 131 can be 5µm~10µm, 10µm~20µm, 20µm~30µm, or 30µm~40µm. For example, the amplitude of the corrugated structure of the first part 131 can be 5µm, 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, or 40µm.

[0067] The amplitude of the corrugated structure in the third part 133 can be 10µm~20µm, 20µm~30µm, 30µm~40µm, 40µm~50µm, or 50µm~60µm. For example, the amplitude of the corrugated structure in the third part 133 can be 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 55µm, or 60µm.

[0068] The amplitude of the corrugated structure in Part 4 134 can be 15µm~20µm, 20µm~40µm, 40µm~60µm, or 60µm~80µm. For example, the amplitude of the corrugated structure in Part 4 134 can be 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 60µm, 70µm, or 80µm.

[0069] The amplitude of the corrugated structure in each part can be calculated by continuously sampling 3 to 10 turns of the electrode layer. For example, the amplitude of the corrugated structure can be calculated by continuously sampling 3, 4 or 5 turns of the first part 131.

[0070] By controlling the amplitude of the corrugated structure of different parts of the electrode 130 distributed along the width direction, it is possible to avoid the inability of different zones of the electrode 130 to effectively release stress due to the small amplitude of the corrugated structure, and also to avoid the significant shape change of the electrode 130 due to the large amplitude of the corrugated structure in different zones of the electrode 130, thereby avoiding large differences in contact pressure in different parts of the electrode 130.

[0071] In some embodiments, the maximum depth of the corrugated structure of the first part 131 may be less than or equal to 25µm, the maximum depth of the corrugated structure of the third part 133 may be 5µm to 40µm, and the maximum depth of the corrugated structure of the fourth part 134 may be 10µm to 70µm.

[0072] The maximum depth H of the corrugated structure corresponds to the concave dimension of the electrode 130 relative to the adjacent convex dimension, or the protruding dimension of the convex dimension relative to the adjacent concave dimension, that is, the concave or convex dimension along the thickness direction of the core. Figure 6 and Figure 8 The dimension is indicated by the arrow Z. The maximum depth is related to the height of the unevenness of different parts of the electrode 130. The greater the maximum depth, the greater the height of the unevenness of the electrode 130, and the more prominent the undulation of the cross-sectional shape of the electrode 130. The smaller the maximum depth, the smaller the height of the unevenness of the electrode 130, and the more subtle the undulation of the cross-sectional shape of the electrode 130.

[0073] In practice, the maximum depth of the corrugated structure of the first part 131 can be 5µm~10µm, 10µm~15µm, 15µm~20µm, or 20µm~25µm. For example, the amplitude of the corrugated structure of the first part 131 can be 5µm, 10µm, 15µm, 20µm, or 25µm.

[0074] The maximum depth of the corrugated structure in the third part 133 can be 5µm~10µm, 10µm~20µm, 20µm~30µm, or 30µm~40µm. For example, the maximum depth of the corrugated structure in the first part 131 can be 5µm, 15µm, 20µm, 25µm, 30µm, 35µm, or 40µm.

[0075] The maximum depth of the corrugated structure of the fourth part 134 can be 10µm~30µm, 30µm~50µm, or 50µm~70µm. For example, the maximum depth of the corrugated structure of the fourth part 134 can be 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 60µm, or 70µm.

[0076] By controlling the maximum depth of the corrugated structure in different parts of the electrode 130, it is possible to avoid the inability to properly match the tension differences in different parts of the electrode 130 due to the small maximum depth of the corrugated structure, and it is also possible to avoid the difficulty of electrolyte wetting in different parts of the electrode 130 due to the large maximum depth of the corrugated structure.

[0077] In some embodiments, along the first direction, the dimensions of the first part 131, the third part 133, and the fourth part 134 may be greater than or equal to 5% of the dimensions of the electrode assembly 13, or the dimensions of the first part 131, the third part 133, and the fourth part 134 may be greater than or equal to 10 mm.

[0078] The dimension W1 of the first part 131 along the first direction corresponds to the width dimension of the first part 131, the dimension W3 of the third part 133 along the first direction corresponds to the width dimension of the third part 133, the dimension W4 of the fourth part 134 along the first direction corresponds to the width dimension of the fourth part 134, and the dimension W of the electrode assembly 13 along the first direction corresponds to the width of the electrode assembly 13.

[0079] By controlling the minimum width of different sections of the electrode 130, it can be ensured that different sections of the electrode 130 have a certain range to form a corrugated structure with a specific range of undulations, thereby ensuring that the corrugated structure of different sections can better adapt to the distribution areas of different stresses of the electrode 130.

[0080] In practice, the width of the first part 131, the third part 133, and the fourth part 134 can be controlled to be no less than 5% of the width of the electrode assembly 13, or the width of the first part 131, the third part 133, and the fourth part 134 can be controlled to be no less than 10 mm. For example, the width of the first part 131, the third part 133, and the fourth part 134 can be 5%, 6%, 7%, or 8% of the width of the electrode assembly 13. The width of the first part 131, the third part 133, and the fourth part 134 can also be 10 mm, 11 mm, 12 mm, or 13 mm.

[0081] In some embodiments, along the first direction, the size W1 of the first part 131 can be 40% to 80% of the size W of the electrode assembly 13, and the size W2 of the second part 132 can be 10% to 30% of the size W of the electrode assembly 13.

[0082] The dimension W1 of the first part 131 along the first direction corresponds to the width dimension of the first part 131, the dimension W2 of the second part 132 along the first direction corresponds to the width dimension of the second part 132, and the dimension W of the electrode assembly 13 along the first direction corresponds to the width dimension of the electrode assembly 13.

[0083] By controlling the width of the first part 131 and the width of the second part 132 relative to the width of the electrode assembly 13, it can be ensured that different sections of the electrode 130 have sufficient width, thereby ensuring that corrugated structures with different amplitudes form a sufficient distribution range in different parts of the electrode 130, so as to ensure the improvement effect on the interlayer contact pressure of the electrode.

[0084] In practice, the width of the first part 131 can be 40%, 50%, 60%, 70%, or 80% of the width of the electrode assembly 13. The width of the second part 132 can be 10%, 15%, 20%, 25%, or 30% of the width of the electrode assembly 13.

[0085] In some embodiments, the preset number of turns is less than or equal to 0.3N, where N is the number of turns of the electrode 130.

[0086] In other words, the electrode assembly 13 can have a corrugated structure on the electrode sheet 130 within a range of 0.3N turns from the inside out. N corresponds to the total number of turns of the electrode sheet 130. For example, when the total number of turns of the electrode sheet 130 is 110, the electrode sheet 130 within 20, 25, or 30 turns from the inside out of the electrode assembly 13 can have a corrugated structure. By controlling the range of the preset number of turns, it is possible to avoid the inability to effectively improve the contact pressure difference between the inner layers of the electrode assembly 13 due to a small preset number of turns, and it is also possible to avoid deformation accumulation due to a large preset number of turns, thereby avoiding adverse effects on the outer electrode sheet 130b (i.e., the part of the electrode sheet 130 near the outer ring of the core after winding).

[0087] In practice, the preset number of revolutions can also be set to 0.4N, 0.5N, or 0.6N.

[0088] In some embodiments, the ratio between the standard deviation and the average value of the amplitude of the corrugated structures located in the first part 131 and / or the second part 132 of different layers is less than or equal to 0.3.

[0089] The standard deviation corresponds to the amplitude variation of the corrugated structure at various locations within the same partition, while the average value corresponds to the average range of the amplitude of the corrugated structure at various locations within the same partition. By comparing the ratio between the standard deviation and the average value, the degree of difference in the amplitude of the corrugated structure at various locations within the same partition can be determined, thereby identifying the degree of amplitude variation of the corrugated structure at various locations within the same partition. By controlling the ratio between the standard deviation and the average value of the amplitude of the corrugated structure in the first part 131 or the second part 132, large differences in the undulation of the corrugated structure at the center or edge of different layers of the electrode can be avoided. This prevents the inability to effectively control the shape between electrode layers, avoids large differences in the improvement of the interlayer contact effect between different layers of the electrode, and thus avoids differences in contact pressure in the core thickness direction.

[0090] In practice, the standard deviation and average value can be calculated by the concave size of some concave parts and / or the protruding size of the convex parts. For example, the standard deviation and average value of the amplitude of the corrugated structure in the first part 131 or the second part 132 can be calculated based on the amplitude corresponding to 3 to 5 concave parts / or convex parts, thereby obtaining the ratio between the standard deviation and average values.

[0091] In some embodiments, the gap between the first part 131 of two adjacent electrode layers 130 with a corrugated structure can be less than or equal to 25µm, and the gap between the second part 132 of two adjacent electrode layers 130 with a corrugated structure can be 5µm to 60µm.

[0092] In practice, the gap between the first portion 131 of two adjacent electrode layers 130 with a corrugated structure can be 5µm~10µm, 10µm~15µm, 15µm~20µm, or 20µm~25µm. For example, the gap between the first portion 131 of two adjacent electrode layers 130 with a corrugated structure can be 5µm, 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 55µm, or 60µm.

[0093] The gap between the second part 132 of two adjacent electrode layers 130 with a corrugated structure can be 5µm~10µm, 10µm~20µm, 20µm~40µm, or 40µm~60µm. For example, the gap between the second part 132 of two adjacent electrode layers 130 with a corrugated structure can be 5µm, 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 55µm, or 60µm.

[0094] By controlling the gap between the same partition portion of two adjacent electrode layers 130, the distance between two adjacent electrode layers 130 with a corrugated structure in the inner ring of the core can be controlled, thereby ensuring that the distance between two adjacent electrode layers 130 with a corrugated structure in the inner ring of the core is within a certain range.

[0095] By controlling the gap between the first part 131 of two adjacent layers of electrode 130 with a corrugated structure to no more than 25µm, it is possible to avoid the gap between the first part 131 of the two adjacent layers of electrode 130 with a corrugated structure being too small, which would lead to difficulty in electrolyte wetting. It is also possible to avoid the gap between the first part 131 of the two adjacent layers of electrode 130 with a corrugated structure being too large, which would occupy the inner ring space and thus avoid affecting the cell capacity.

[0096] By controlling the gap between the second part 132 of the two adjacent layers of electrode 130 with a corrugated structure to a range of 5µm to 60µm, it is possible to avoid the gap between the second part 132 of the two adjacent layers of electrode 130 with a corrugated structure being too small, which would lead to difficulty in electrolyte wetting. It is also possible to avoid the gap between the second part 132 of the two adjacent layers of electrode 130 with a corrugated structure being too large, which would occupy the inner ring space and thus avoid affecting the cell capacity.

[0097] In some embodiments, the electrode 130 may include a current collector and an active material layer stacked together. Along a first direction, the electrode 130 is provided with adjacent coated areas and uncoated areas, the active material layer is located in the coated areas, and a corrugated structure is formed in the coated areas.

[0098] The current collector is the core component of electrode 130 that carries the active material of the electrode and collects current. In lithium-ion batteries, the positive electrode uses aluminum foil with a thickness of 10μm to 20μm as the current collector, and the negative electrode uses copper foil with a thickness of 6μm to 12μm as the current collector. Sodium-ion batteries can use aluminum foil as the current collector for both the positive and negative electrodes. In sodium batteries, using aluminum foil instead of copper foil as the negative electrode current collector helps reduce costs.

[0099] The active material layer corresponds to the active material placed on the current collector and is the core material in electrode 130 that directly participates in the electrochemical reaction and determines the energy density and power performance. The positive electrode active material is placed on the current collector of the positive electrode 1301, and the negative electrode active material is placed on the current collector of the negative electrode 1302. Common types of positive electrode active materials include lithium iron phosphate (LiFePO4, LFP) and lithium manganese iron phosphate (LiMn). x Fe 1-x PO4, LMFP), ternary materials (LiNi) x Mn n Systems such as Co2O2 and NMC are used, and the negative electrode active materials include artificial graphite, natural graphite and their composite materials.

[0100] The active material is applied to the coating area corresponding to the current collector, while the uncoated area corresponds to the area where the tabs are located on the electrode 130. The corrugated structure is formed in the coating area of ​​the electrode 130, that is, in the area of ​​the electrode 130 where the active material is located. This avoids affecting the uncoated area and the tab structure, and also controls the extension range of the corrugated structure, preventing the formation of wavy edges on the electrode 130.

[0101] In practice, the positive electrode 1301 includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive active material. As an example, the positive current collector has two opposing surfaces, and the positive electrode film layer is disposed on either or both of the opposing surfaces of the positive current collector.

[0102] The positive electrode current collector can be a metal foil or a composite current collector. For example, the metal foil may include, but is not limited to, aluminum foil. The composite current collector may include a base layer and a metal layer located on at least one surface of the base layer. For example, the base layer may be a polymer material base layer, including but not limited to polypropylene (PP) base layer, polyethylene terephthalate (PET) base layer, polybutylene terephthalate (PBT) base layer, polystyrene (PS) base layer, or polyethylene (PE) base layer. The material of the metal layer may include, but is not limited to, aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy.

[0103] The positive electrode active material includes lithium salts, which can be lithium-containing phosphates. Lithium-containing phosphates refer to phosphate materials containing lithium elements and can be detected by any method known in the art. For example, they can be detected by combining X-ray diffraction with energy dispersive spectroscopy (EDS) or inductively coupled plasma mass spectrometry (ICP-MS). As examples, lithium-containing phosphates include, but are not limited to, lithium iron phosphate, lithium iron phosphate doped and modified materials, or lithium iron phosphate coated and modified materials.

[0104] For example, the positive electrode active material can also be a high-voltage system with an operating voltage greater than or equal to 4.3V, such as high-nickel ternary materials, high-voltage spinel materials, lithium manganese phosphate, or lithium-rich manganese-based materials. For example, high-nickel ternary materials such as LiNi... 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM622), LiNi 0.8 Co 0.15 Al 0.05 O2 (NCA) and other compounds possess operating voltages of 4.3V~4.6V and high specific capacity, making them ideal cathode choices for high-voltage lithium metal batteries. High-voltage spinel LiNi... 0.5 Mn 1.5 O4 operates at a voltage up to 4.7V, perfectly matching its high voltage stability. Lithium manganese iron phosphate, a type of lithium manganese phosphate, is an emerging high-voltage phosphate material that combines safety and high-voltage characteristics.

[0105] However, this application is not limited to the materials listed above, and other materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone, or in combination of two or more. The positive electrode film layer may also include a binder and / or a conductive agent.

[0106] The binder may be selected from one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), or polyacrylic acid (PAA). The conductive agent may be selected from one or more of conductive carbon black, superconducting carbon, Ketjen black, carbon dots, acetylene black, graphene, carbon nanotubes, carbon nanofibers, or graphite.

[0107] The negative electrode 1302 includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer comprising a negative electrode active material. As an example, the negative current collector has two opposing surfaces, and the negative electrode film layer is disposed on either or both of the opposing surfaces of the negative current collector.

[0108] The negative electrode current collector can be a metal foil or a composite current collector. For example, the metal foil may include, but is not limited to, copper foil. The composite current collector may include a base layer and a metal layer located on at least one surface of the base layer. For example, the base layer can be a polymer material, including but not limited to polypropylene (PP) base layer, polyethylene terephthalate (PET) base layer, polybutylene terephthalate (PBT) base layer, polystyrene (PS) base layer, or polyethylene (PE) base layer. The material of the metal layer may include, but is not limited to, copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, or silver alloys.

[0109] The negative electrode active material can be any negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material can be at least one of the following materials, including but not limited to: graphite, carbon materials, silicon-based materials, tin-based materials, or lithium titanate. Graphite can be artificial graphite or natural graphite. Carbon materials can be soft carbon or hard carbon. Silicon-based materials can be selected from at least one of elemental silicon, silicon oxide, silicon-carbon compounds, silicon-nitrogen compounds, and silicon alloys. Tin-based materials can be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other materials that can be used as negative electrode active materials for battery cells can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0110] Optionally, the negative electrode film may also include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0111] Optionally, the negative electrode film layer may also include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0112] Optionally, the negative electrode film may also include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0113] In some embodiments, along the second direction ( Figure 8 (In the direction indicated by the middle arrow Y), the electrode 130 may include a main body 135 and curved portions 136 located on both sides of the main body 135. A corrugated structure is formed on the main body 135, and the second direction is the direction intersecting the first direction.

[0114] The second direction is parallel to the width direction of the core. The main body 135 corresponds to the relatively straight portion of the electrode 130, and the curved portion 136 corresponds to the relatively curved portion of the electrode 130. That is, the main body 135 is located in the straight portion of the core, and the curved portion 136 is located in the curved portion of the core. A corrugated structure is formed in the main body 135, that is, a corrugated structure is formed in the relatively straight portion of the electrode 130, thereby avoiding the relatively curved portion of the electrode 130.

[0115] In practice, the bent portion 136 of the electrode 130 is subject to significant stress. By forming a corrugated structure on the main body 135, adverse effects on the bent portion 136 of the electrode 130 can be avoided. Figure 8 As shown, the electrode 130 within the area defined by the dashed box can form a corrugated structure near the inner ring of the main body 135.

[0116] In some embodiments, the electrode assembly 13 may further include a diaphragm 1303, which is disposed adjacent to the electrode 130. Along a first direction, the diaphragm 1303 includes a middle portion and edge portions located at both ends of the middle portion. At least two adjacent layers of the diaphragm 1303 located within a predetermined number of turns from the inside to the outside of the electrode assembly 13 have a corrugated structure, and the amplitude of the corrugated structure in the middle portion is smaller than the amplitude of the corrugated structure in the edge portion.

[0117] The separator 1303 is located between the positive electrode 1301 and the negative electrode 1302, preventing direct contact between them. When the electrode 130 is wound to form a core, the separator 1303 is wound simultaneously with both the positive and negative electrode 1301, ensuring that the separator 1303 is positioned between them. At least two adjacent separator layers 1303 located on the inner ring of the core can have a corrugated structure, the corrugated structure of the separator 1303 being substantially the same as or identical to the corrugated structure of the electrode 130. The corrugated structure in the middle of the separator 1303 corresponds to the corrugated structure of the first part 131 of the electrode 130, and the corrugated structure at the edge of the separator 1303 corresponds to the corrugated structure of the second part 132 of the electrode 130.

[0118] In other words, the diaphragm 1303 can also form a corrugated structure similar to the corrugated structure of the electrode 130. The amplitude of the corrugated structure at the edge of the diaphragm 1303 is greater than that at the middle. The corrugated structure of the diaphragm 1303 can match the corrugated structure of the electrode 130, thereby avoiding stress on the electrode 130 and also avoiding affecting the shape of the corrugated structure of the electrode 130.

[0119] The material of the diaphragm 1303 can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. This application does not impose any particular limitation on the type of diaphragm 1303; for example, a porous diaphragm with chemical and mechanical stability can be selected. The diaphragm 1303 can be a single-layer film or a multi-layer composite film, without particular limitation. When the diaphragm 1303 is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0120] In some specific examples, the separator 1303 may include polypropylene (PP) separators, polyethylene (PE) separators, PP / PE / PP three-layer composite separators, ceramic-coated separators, high-strength polymer separators, or functionalized composite separators. PP and PE separators typically have a thickness of 12μm to 25μm and a porosity of 30% to 50%, exhibiting good mechanical strength and chemical stability. Ceramic-coated separators, with a coating of ceramic materials such as Al2O3, SiO2, and TiO2 (coating thickness of 2μm to 5μm) on a polyolefin-based membrane, improve high-temperature resistance (thermal shut-off temperature >160℃) and puncture resistance. High-strength polymer separators (such as polyimide PI, polyethylene terephthalate PET, and aramid nanofiber separators) possess excellent mechanical properties and high-temperature resistance. Functionalized composite separators (such as separators containing solid electrolyte coatings or lithiophilic coatings) can further enhance lithium deposition stability.

[0121] The electrolyte acts as a conductor of ions between the positive electrode 1301 and the negative electrode 1302. This application does not specifically limit the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel-like, or entirely solid. For example, the electrolyte may be an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent. For example, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate. For example, solvents may be selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4 At least one of butyrolactone, sulfolane, dimethyl sulfone, methyl sulfone, and diethyl sulfone.

[0122] The electrolyte may also include additives. Additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery cell 10, such as additives that improve the overcharge performance of the battery cell 10, additives that improve the high-temperature or low-temperature performance of the battery cell 10, etc.

[0123] The battery cell 10 provided in this application embodiment can be widely used in battery fields requiring high energy density and long cycle life, including high-end electric vehicle battery systems, portable electronic devices, and large-scale energy storage power stations. The battery cell 10 provided in this application embodiment can achieve large-capacity energy storage, comprehensively improving energy density, cycle life, and safety performance. It can meet the needs of long-term energy storage, achieving long-term energy storage of 4 hours or more, for example, it can be applied to energy storage scenarios such as 5 hours, 6 hours, and 8 hours. Long-term energy storage refers to the ability to continuously discharge at rated power for 4 hours or even longer, or to achieve large-scale, low-cost energy storage for several days or months.

[0124] Some embodiments of this application also provide a method for preparing a single battery cell, such as... Figure 9 As shown, the preparation method of a single battery cell includes the following steps: Step S110: The electrode sheet is wound, and different magnitudes of force are applied to the first and second regions of the electrode sheet distributed along the first direction before the electrode sheet is wound.

[0125] By applying different forces to different areas of the electrode, the electrode can be compensated before winding, thereby adapting to the tension difference between the central and edge areas along the width direction of the electrode.

[0126] Step S120: After the electrode sheet is wound a predetermined number of turns, stop applying different magnitudes of force to the first and second regions of the electrode sheet distributed along the first direction before winding the electrode sheet, and continue winding the electrode sheet to obtain the electrode assembly.

[0127] The electrode assembly includes a positive electrode, a negative electrode, and a separator. The different electrodes and separator are formed into a whole using a winding process. The tension difference compensation of the electrodes occurs in the inner ring of the electrode assembly. In the electrode area near the inner ring, the bending deformation formed by the electrodes during winding is greater. Therefore, by applying a compensating force, the interlayer contact effect of the inner ring electrodes can be improved, thereby ensuring the consistency of interlayer contact pressure in different parts of the inner ring electrodes.

[0128] Step S130: Place the electrode assembly into the housing.

[0129] The housing is the foundation for housing the electrode assembly and forms the main part of the battery cell's encapsulation. An opening at the top of the housing allows the electrode assembly to be inserted. This opening is located on the opposite side of the bottom wall of the housing. The area of ​​the bottom wall can be larger or smaller than the area of ​​the side wall; that is, the electrode assembly can be inserted horizontally or vertically along the opening. The housing can be made of lightweight and structurally strong aluminum.

[0130] Step S140: Connect the cover of the top cover assembly to the opening of the housing, and connect the terminal post of the top cover assembly to the tab of the electrode plate to form a battery cell.

[0131] The cover and casing work together to form the encapsulation shell of the battery cell. Different terminals work with the cover to form a top cover assembly, which includes a terminal structure, an explosion-proof structure, and a liquid filling structure. The first mating part of the positive terminal passes through the first terminal hole in the cover and connects to the first connecting piece. After the first connecting piece is basically flush with the first mating part, the junction can be butt-welded to fix the first connecting piece and the first mating part. Similarly, the negative terminal is fixed to the second connecting piece by butt welding.

[0132] In addition, upper plastic is provided between the first connecting part of the positive terminal and the cover, and between the second connecting part of the negative terminal and the cover, to insulate the terminal structure from the cover and prevent short circuits caused by using a metal cover. Lower plastic can be provided between the first connecting piece and the cover, and between the second connecting piece and the cover, for insulation. A sealing ring can also be provided within the lower plastic inner ring to ensure a tight seal.

[0133] The first connecting piece is used to connect with the positive electrode tab of the electrode assembly, and the second connecting piece is used to connect with the negative electrode tab of the electrode assembly.

[0134] After the cover and casing are welded together, the assembly of the various parts of the battery cell is complete. The cover can be sealed to the opening of the casing to ensure the airtightness of the casing. Then, electrolyte can be injected into the casing, and a formation process can be performed to form a battery cell that can function normally.

[0135] In practice, a differentiated force-applying winding mechanism with at least three independent force-applying zones along the width direction can be adopted. Each force-applying zone can independently adjust its normal pressure, tangential damping, or geometric path compensation to achieve active zonal control of the force applied to the wide-width electrode sheet before winding. The normal pressure corresponds to the vertical contact pressure applied to the electrode sheet plane by each force-applying unit, and the normal pressure of each force-applying zone is independently adjustable. The tangential damping corresponds to the frictional resistance or transmission damping applied to the electrode sheet by each force-applying unit to adjust the winding tension distribution in different areas. The geometric path compensation corresponds to the differentiated roller surface shape or spatial position of each force-applying unit, applying differentiated geometric constraints to the winding portions of different areas of the electrode sheet.

[0136] The specific implementation forms of the zoned force application mechanism include at least one of the following: 1. Sectional pressure roller 21 ( Figure 10 As shown), the roller body is divided into at least three roller sections with independently adjustable contact pressure along the width direction. Each roller section is subjected to different normal pressures through an independent cylinder, elastic element 22 or hydraulic system. 2. A zoned damping mechanism is provided, with at least three damping sections with different tangential resistance parameters along the width direction. Different friction coefficients, braking torques, or tension settings are set for each section to adjust the winding tension in different areas of the electrode width direction. 3. Compensating roller 31 ( Figure 11 As shown, the roller surface has a specific contour distribution along the width direction, including crown-shaped, concave arc-shaped, or stepped shapes. Differentiated contact support is applied to different areas of the electrode through the roller surface geometry.

[0137] In the partitioned pressure roller implementation, the winding equipment is equipped with partitioned pressure rollers at the position of the last guide roller before the electrode enters the winding spindle. The roller body is divided into a central section and an edge section along the width direction of the electrode (corresponding to the width distribution of the first and second parts of the electrode), and each section is equipped with an independent cylinder or elastic pressure unit. The normal pressure applied to each section can be set independently. During the winding process, the pressure parameters of the central section and the edge section are pre-calibrated according to the electrode width, the mechanical properties of the substrate, and the target partition compensation amount, or adjusted in real time through a closed-loop pressure feedback system. During the electrode winding process, different width zones are subjected to differentiated winding constraint forces, thereby forming a deformation characteristic distribution corresponding to the applied force zones between layers. After sufficient layers are stacked, a statistically repeatable partitioned interlayer structure is formed inside the core.

[0138] In the implementation of the zoned damping mechanism, the winding equipment is configured with damping tension units zoned along the width direction on the electrode conveying path. Each damping section applies different tangential resistance to different areas along the width direction of the electrode by setting differentiated braking torque or friction coefficient parameters, thereby adjusting the local tension of winding in different areas of the electrode. The parameter settings of each damping section aim to compensate for the tension in the width direction of the wide electrode, so that different areas of the electrode achieve the expected local winding force distribution during winding, reducing the force difference in the width direction and improving the morphological regularity of the core.

[0139] In the implementation of the compensation roller, at least one compensation roller with a specific profile curve in the width direction is configured in the guide roller system of the winding equipment. The roller surface shape is designed according to the electrode width and interlayer shape distribution. The roller surface profile of the compensation roller forms differentiated contact support in the width direction, applying different bending preloads or tension pre-distributions to different areas of the electrode, thereby passively compensating for tension differences in the electrode during the winding process. The roller surface profile parameters of the compensation roller (including profile shape, compensation curve slope, and compensation zone width) can be matched with the electrode width, substrate lateral stiffness, and winding speed of the target battery cell, and can be recalibrated when switching to new electrode specifications or material systems.

[0140] In the combined implementation, the zoned pressure roller, zoned damping mechanism, and compensating roller can be flexibly combined according to specific process requirements to construct a multi-level collaborative zoned force application system, further improving the accuracy and stability of the winding force control in the width direction. The number of zones in the above implementations is not limited to three zones, and can be expanded to five zones or more sections according to the electrode width and process objectives.

[0141] Some embodiments of this application also provide a battery device, which includes the battery cell described above, or a battery cell manufactured by the method described above for preparing the battery cell.

[0142] Battery devices include one or more of the following: battery modules, battery packs, and energy storage batteries.

[0143] like Figure 12 and Figure 13 As shown, the battery pack 100 includes a housing 110 and multiple battery modules 120 located within the housing 110. Each battery module 120 includes multiple individual battery cells 10. The housing 110 includes a bottom frame 110a and a cover 110b. The bottom frame 110a defines the position of the battery modules 120, and the cover 110b accommodates the battery modules 120. In practice, the number of battery modules 120 within the housing 100 can be one or more. The housing 100 can also accommodate the battery modules at the bottom and at the top.

[0144] The housing 110 provides a receiving space for the battery cell 10, and the housing 10 can adopt various structures. In some embodiments, the housing 110 may include a first part and a second part, which overlap each other, and the first part and the second part together define a receiving space for accommodating the battery cell 10. The second part may be a hollow structure with one end open, and the first part may be a plate-like structure, with the first part covering the open side of the second part so that the first part and the second part together define the receiving space; the first part and the second part may also be hollow structures with one side open, with the open side of the first part covering the open side of the second part. Of course, the housing formed by the first part and the second part can be of various shapes, such as a cylinder, a cuboid, etc.

[0145] In the battery device, the battery cell 10 can be a single cell or multiple cells. Multiple battery cells 10 can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple battery cells 10 are connected in both series and parallel configurations. Multiple battery cells 10 can be directly connected in series, parallel, or a combination thereof to form a whole, which is then housed within the housing 110. Alternatively, the battery device can also consist of multiple battery cells 10 first connected in series, parallel, or a combination thereof to form battery modules, which are then connected in series, parallel, or a combination thereof to form a whole, which is also housed within the housing 110.

[0146] The battery device may also include other structures, such as a busbar for electrical connection between multiple battery cells 10.

[0147] Some embodiments of this application also provide an energy storage device, which includes the battery device described above, and the battery device is used to store electrical energy.

[0148] Energy storage devices include, but are not limited to, residential energy storage cabinets, commercial energy storage cabinets, energy storage containers, energy storage racks, energy storage power stations, energy storage battery packs, or portable energy storage systems. Energy storage devices may also include energy management systems (EMS), battery management systems (BMS), and power conversion systems (PCS).

[0149] Figure 14 The diagram illustrates the energy storage cabinet 200, which uses a cabinet 210 to house the battery device. Figure 15 The diagram illustrates the energy storage container, with container 300 using container 310 to house the battery device.

[0150] Some embodiments of this application also provide an electrical device, which includes the battery device described above, and the battery device is used to provide electrical energy.

[0151] Electrical devices include, but are not limited to, mobile phones 400 ( Figure 16 (As shown), tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0152] Those skilled in the art will understand that the above embodiments are specific implementations of this application, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of this application.

Claims

1. A battery cell, characterized in that, include: The casing has an opening; A top cover assembly includes a cover body disposed at the opening and an electrode post connected to the cover body; An electrode assembly is disposed within the housing. The electrode assembly includes an electrode sheet wound from the inside out. The electrode sheet is provided with an electrode tab, which is connected to the electrode post. Along a first direction, the electrode includes a first part and a second part located at both ends of the first part. The electrode assembly has a corrugated structure in at least two adjacent layers of the electrode within a preset number of turns from the inside to the outside. The amplitude of the corrugated structure in the first part is smaller than the amplitude of the corrugated structure in the second part.

2. The battery cell according to claim 1, characterized in that, Along the first direction, the size of the electrode assembly is 200mm~600mm.

3. The battery cell according to claim 1, characterized in that, The amplitude of the corrugated structure in the first part is 5µm to 60µm, and the amplitude of the corrugated structure in the second part is 10µm to 80µm.

4. The battery cell according to claim 1, characterized in that, Along the first direction, the second part includes a third part and a fourth part arranged adjacent to each other, the third part being located between the first part and the fourth part, and the amplitude of the corrugated structure of the third part being smaller than the amplitude of the corrugated structure of the fourth part.

5. The battery cell according to claim 4, characterized in that, The mean difference between the amplitude of the corrugated structure in the third part and the amplitude of the corrugated structure in the fourth part is greater than or equal to 3µm.

6. The battery cell according to claim 4, characterized in that, The amplitude of the corrugated structure in the first part is 5µm to 40µm, the amplitude of the corrugated structure in the third part is 10µm to 60µm, and the amplitude of the corrugated structure in the fourth part is 15µm to 80µm.

7. The battery cell according to claim 4, characterized in that, The maximum depth of the corrugated structure in the first part is less than or equal to 25µm, the maximum depth of the corrugated structure in the third part is 5µm to 40µm, and the maximum depth of the corrugated structure in the fourth part is 10µm to 70µm.

8. The battery cell according to claim 4, characterized in that, Along the first direction, the dimensions of the first part, the third part, and the fourth part are greater than or equal to 5% of the dimensions of the electrode assembly, or the dimensions of the first part, the third part, and the fourth part are greater than or equal to 10 mm.

9. The battery cell according to claim 1, characterized in that, Along the first direction, the size of the first part is 40% to 80% of the size of the electrode assembly, and the size of the second part is 10% to 30% of the size of the electrode assembly.

10. The battery cell according to claim 1, characterized in that, The preset number of turns is less than or equal to 0.3N, where N is the number of turns of the electrode.

11. The battery cell according to claim 1, characterized in that, The ratio between the standard deviation and the mean of the amplitude of the corrugated structure located in the first and / or second parts of different layers is less than or equal to 0.

3.

12. The battery cell according to claim 1, characterized in that, The gap between the first portion of two adjacent layers of the electrode having the corrugated structure The gap between the second part of two adjacent layers of the electrode with the corrugated structure is less than or equal to 25µm and is 5µm to 60µm.

13. The battery cell according to claim 1, characterized in that, The electrode includes a current collector and an active material layer stacked together. Along the first direction, the electrode has adjacent coated areas and uncoated areas. The active material layer is located in the coated area, and the corrugated structure is formed in the coated area.

14. The battery cell according to claim 1, characterized in that, Along the second direction, the electrode includes a main body portion and curved portions located on both sides of the main body portion, the corrugated structure being formed in the main body portion, and the second direction being a direction intersecting the first direction.

15. The battery cell according to claim 1, characterized in that, The electrode assembly further includes a diaphragm disposed adjacent to the electrode sheet. Along the first direction, the diaphragm includes a middle portion and edge portions located at both ends of the middle portion. At least two adjacent layers of the diaphragm within a preset number of turns from the inside to the outside of the electrode assembly have a corrugated structure. The amplitude of the corrugated structure in the middle portion is smaller than the amplitude of the corrugated structure in the edge portion.

16. A method for preparing a battery cell according to any one of claims 1 to 15, characterized in that, include: The electrode sheet is wound, and different magnitudes of force are applied to the first region and the second region of the electrode sheet distributed along the first direction before the electrode sheet is wound. After the electrode sheet is wound a predetermined number of turns, the application of different magnitudes of force to the first and second regions of the electrode sheet distributed along the first direction is stopped before the electrode sheet is wound, and the electrode sheet is wound again to obtain an electrode assembly; Place the electrode assembly into the housing; The cover of the top cover assembly is connected to the opening of the housing, and the terminal of the top cover assembly is connected to the tab of the electrode plate to form a battery cell.

17. A battery device, characterized in that, Includes the battery cell according to any one of claims 1 to 15, or the battery cell made by the method for preparing the battery cell according to claim 16.

18. An energy storage device, characterized in that, Includes the battery device of claim 17, the battery device being used for storing electrical energy.

19. An electrical appliance, characterized in that, Includes the battery device of claim 17, the battery device being used to provide electrical energy.

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